Question

Look at the graph. It shows a typical variation of populations of predators (wolves, tigers etc.) and prey (deer, rabbits etc.) in a habitat such as a forest.



Answer these questions.
1. Why is the predator population always lower than the prey population?
2. Point A is the rainy season. Why is the prey population increasing?
3. Why does the predator population starts increasing after the increase in the prey population?
4. As the predator population increases, why does the prey population starts declining (point B)?
5. Why does the predator population now start to decrease (point C)?
6. Will the graph maintain the same shape if a calamity such as disease struck the prey and they died in large numbers? What do you expect will happen?

Answer 1

1. Lower predator population than the prey ensures that prey population does not reach to extent of extinction. If predator population exceeds the prey population, it could lead to their extinction.

2. After the rainy season, the availability of food increases for the prey and conditions become favourable for them.

3. Increase in prey population means increased availability of food for predators. The predators population also increase but only to a certain extent.

4. If the predator population is going to increase, so will their demand for food. More number of prey will be feeded on which would result in a decline in their population.

5. At point C, we can see that the population of prey is also decreasing. If the population of prey decreases, the availability of food for predators also decreases.

6. No, the graph will not remain the same if a calamity strucks and kills most of the prey. If prey will die in large number, there will be a scarcity of food for the predators and eventually they would also die.